Bifurcated graft deployment systems and methods

ABSTRACT

A method for deploying an endoluminal vascular prosthesis using a deployment catheter that has at least a main graft portion and a first branch graft portion. The deployment catheter preferably comprises an elongate, flexible catheter body having a proximal end and a distal end, and an outer sheath and an inner core that is axially moveable with respect to the outer sheath. The catheter preferably comprises a main graft restraint that has a main graft release mechanism comprising a main graft sheath and a suture threaded through a plurality of the openings in the main graft sheath. The catheter further comprises at least one branch graft restraint comprising at least one branch graft release mechanism.

This application is a continuation of U.S. patent application Ser. No.12/101,863, filed Apr. 11, 2008, which application is herebyincorporated by reference and made part of the present disclosure as iffully set forth herein.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to endoluminal vascular prosthesisdeployment, and in particular, to a deployment system for a bifurcatedgraft having at least one peelable sheath.

2. Description of the Related Art

An abdominal aortic aneurysm is a sac caused by an abnormal dilation ofthe wall of the aorta, a major artery of the body, as it passes throughthe abdomen. The abdomen is that portion of the body which lies betweenthe thorax and the pelvis. It contains a cavity, known as the abdominalcavity, separated by the diaphragm from the thoracic cavity and linedwith a serous membrane, the peritoneum. The aorta is the main trunk, orartery, from which the systemic arterial system proceeds. It arises fromthe left ventricle of the heart, passes upward, bends over and passesdown through the thorax and through the abdomen to about the level ofthe fourth lumbar vertebra, where it divides into the two common iliacarteries.

The aneurysm usually arises in the infrarenal portion of the diseasedaorta, for example, below the kidneys. When left untreated, the aneurysmmay eventually cause rupture of the sac with ensuing fatal hemorrhagingin a very short time. High mortality associated with the rupture ledinitially to transabdominal surgical repair of abdominal aorticaneurysms. Surgery involving the abdominal wall, however, is a majorundertaking with associated high risks. There is considerable mortalityand morbidity associated with this magnitude of surgical intervention,which in essence involves replacing the diseased and aneurysmal segmentof blood vessel with a prosthetic device which typically is a synthetictube, or graft, usually fabricated of Polyester, Urethane, DACRON™,TEFLON™, or other suitable material.

To perform the surgical procedure requires exposure of the aorta throughan abdominal incision which can extend from the rib cage to the pubis.The aorta must be closed both above and below the aneurysm, so that theaneurysm can then be opened and the thrombus, or blood clot, andarteriosclerotic debris removed. Small arterial branches from the backwall of the aorta are tied off. The DACRON™ tube, or graft, ofapproximately the same size of the normal aorta is sutured in place,thereby replacing the aneurysm. Blood flow is then reestablished throughthe graft. It is necessary to move the intestines in order to get to theback wall of the abdomen prior to clamping off the aorta.

If the surgery is performed prior to rupturing of the abdominal aorticaneurysm, the survival rate of treated patients is markedly higher thanif the surgery is performed after the aneurysm ruptures, although themortality rate is still quite high. If the surgery is performed prior tothe aneurysm rupturing, the mortality rate is typically slightly lessthan 10%. Conventional surgery performed after the rupture of theaneurysm is significantly higher, one study reporting a mortality rateof 66.5%. Although abdominal aortic aneurysms can be detected fromroutine examinations, the patient may experience any pain from thecondition. Thus, if the patient is not receiving routine examinations,it is possible that the aneurysm will progress to the rupture stage,wherein the mortality rates are significantly higher.

Disadvantages associated with the conventional, prior art surgery, inaddition to the high mortality rate include the extended recovery periodassociated with such surgery; difficulties in suturing the graft, ortube, to the aorta; the loss of the existing aorta wall and thrombosisto support and reinforce the graft; the unsuitability of the surgery formany patients having abdominal aortic aneurysms; and the problemsassociated with performing the surgery on an emergency basis after theaneurysm has ruptured. A patient can expect to spend from one to twoweeks in the hospital after the surgery, a major portion of which isspent in the intensive care unit, and a convalescence period at homefrom two to three months, particularly if the patient has otherillnesses such as heart, lung, liver, and/or kidney disease, in whichcase the hospital stay is also lengthened. The graft must be secured, orsutured, to the remaining portion of the aorta, which may be difficultto perform because of the thrombosis present on the remaining portion ofthe aorta. Moreover, the remaining portion of the aorta wall isfrequently friable, or easily crumbled.

Since many patients having abdominal aortic aneurysms have other chronicillnesses, such as heart, lung, liver, and/or kidney disease, coupledwith the fact that many of these patients are older, the average agebeing approximately 67 years old, these patients are not idealcandidates for such major surgery.

More recently, a significantly less invasive clinical approach toaneurysm repair, known as endovascular grafting, has been developed.Parodi, et al. provide one of the first clinical descriptions of thistherapy. Parodi, J. C., et al., “Transfemoral Intraluminal GraftImplantation for Abdominal Aortic Aneurysms,” 5 Annals of VascularSurgery 491 (1991). Endovascular grafting involves the transluminalplacement of a prosthetic arterial graft within the lumen of the artery.The embodiments disclosed herein relate to the methods and apparatusesfor deploying bifurcated and non-bifurcated grafts within the lumen orlumens of the blood vessels of the body.

SUMMARY OF SOME EXEMPLIFYING EMBODIMENTS

Certain embodiments described herein are directed to systems, methodsand apparatuses for treating endovascular aneurysms or otherendovascular defects. However, it will be appreciated that the systems,methods and apparatuses may have application to other fields. In someembodiments, the defects being treated may include, but are not limitedto, abdominal aortic aneurysms, subclavian aneurysms, and thoracicaortic aneurysms, to name a few.

In some embodiments, such aneurysms are treated using an endoluminalvascular prosthesis deployment system for deploying an endoluminalvascular prosthesis having at least a main branch and a first branch,comprising a flexible catheter body that preferably comprises an outersheath with a proximal and distal end, an inner core that extendsthrough the outer sheath and is axially moveable with respect to theouter sheath, and a distal tip that is positioned adjacent the distalend of the outer sheath and is coupled to the inner core. In addition,in some embodiments, the deployment system preferably further comprisesa main branch restraint that comprises a tubular member that surroundsand constrains at least the main branch portion, the tubular memberhaving a first portion adjacent a first end of the tubular member, asecond portion adjacent a second end of the tubular member, and anintermediate portion positioned between the first and second portions.In some embodiments, the tubular member preferably comprises a pluralityof perforations.

In some embodiments, the deployment system preferably comprises arelease wire extending through the plurality of perforations andconfigured to tear portions of the tubular member of the main branchrestraint between the perforations to deploy the main branch portionwhen the release wire is proximally retracted by releasing at least oneof the proximal portion or intermediate portion before the distalportion. Additionally, in some embodiments, the deployment systempreferably comprises a first branch restraint that comprises a tubularmember configured to releasably constrain the first branch portion, thefirst branch restraint being coupled to a first branch releasemechanism.

In some embodiments, such aneurysms are treated using a method ofdeploying a bifurcated endoluminal vascular prosthesis comprising a mainbranch segment, a first branch segment, and a second branch segment in apatient's artery, the method comprising the following steps. Althoughthe steps are presented in a particular order, such order is notrequired. Some of the steps listed below could be performed in adifferent order. The prosthesis could be deployed by positioning ahollow guidewire sheath across a bifurcation in a patient's artery andin a contralateral branch of the patient's artery, advancing thedeployment catheter over through an iliac branch of the patient'sartery, the deployment catheter comprising an outer sheath and an innercore that is axially moveable with respect to the outer sheath andconfigured to support the prosthesis within the outer sheath of thedeployment catheter such that, when the inner core is distally advancedrelative to the outer sheath, the prosthesis is caused to be exposed,axially positioning the inner core relative to the outer sheath suchthat the main branch segment, first branch segment, and second branchsegment of the prosthesis is caused to be exposed, positioning theprosthesis in the bifurcation in the patient's artery by manipulatingthe inner core and/or the hollow guidewire sheath so that the mainbranch segment, first branch segment, and second branch segment of theprosthesis are in the desire position, deploying a main graft segment ofthe prosthesis by axially withdrawing a release wire that causes a maingraft segment sheath constraining the main graft segment of theprosthesis to split and deploy the main graft segment, axiallywithdrawing the hollow guidewire sheath until the second branchrestraint is withdrawn from the second branch segment and the secondbranch segment has been deployed, and axially withdrawing the inner coreso as to axially withdraw a first branch restraint coupled thereto untilthe first branch has been deployed.

In some embodiments, the hollow guidewire sheath preferably comprisesdistal and proximal ends and a lumen extending therethrough. In someembodiments, the proximal end of the hollow guidewire assemblypreferably extends from the contralateral branch outside the patient. Insome embodiments, the hollow guidewire sheath is preferably positionedwithin the main branch segment and the second branch segment and ispreferably configured to withdraw a second branch restraint removablypositioned over the second branch segment after a predetermined lengthof the hollow guidewire has been axially withdrawn from the deploymentcatheter.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects and advantages will now be describedin connection with certain embodiments, in reference to the accompanyingdrawings. The illustrated embodiments, however, are merely examples andare not intended to be limiting. The following are brief descriptions ofthe drawings.

FIG. 1A is a schematic representation of an example of a bifurcatedvascular prosthesis that can be used with deployment catheter disclosedherein, positioned at the bifurcation between the abdominal aorta andthe right and left common iliac arteries.

FIG. 1B is an exploded view of the bifurcated prosthesis of FIG. 1A,showing a self-expanding wire support cage separated from an outerpolymeric sleeve.

FIG. 2 is a schematic representation of an embodiment of the deploymentcatheter for delivering a bifurcated prosthesis, with a proximal portionof the main branch portion of the graft at least partially hidden inthis deployed within the aorta.

FIG. 3 is a cross-sectional view of an embodiment of a deploymentcatheter for delivering a bifurcated prosthesis.

FIG. 3A is a cross-sectional view of the embodiment of the deploymentcatheter shown in FIG. 3 taken along line 3A-3A of FIG. 3.

FIG. 3B is a cross-sectional view of an alternative of the embodiment ofthe deployment catheter shown in FIG. 3 taken along line 3B-3B of FIG.3.

FIG. 4 is an enlargement of the portion delineated by the curve 4-4 inFIG. 3.

FIG. 5 is a cross-sectional view of the embodiment of the deploymentcatheter shown in FIG. 3 taken along line 5-5 of FIG. 4.

FIG. 6 is a cross-sectional view of the embodiment of the deploymentcatheter shown in FIG. 3 taken along line 6-6 of FIG. 4.

FIG. 7 is a side view of the main branch portion restraint member of theembodiment of the deployment catheter shown in FIG. 3, before deploymentof the main branch portion of the graft.

FIG. 8 is a top view of the main branch portion restraint member of theembodiment of the deployment catheter shown in FIG. 3, before deploymentof the main branch portion of the graft.

FIG. 9 is an enlarged detail view of FIG. 7 taken along the curve 9 inFIG. 7.

FIG. 10 is an enlarged section view through the axial centerline of themain branch sheath shown in FIG. 7 taken along the curve 10 in FIG. 7.

FIG. 11A is a cross-sectional view of the main branch portion restraintmember shown in FIG. 7 taken along line 11A-11A of FIG. 7.

FIG. 11B is an enlarged detail view of FIG. 11A taken along the curve11B in FIG. 11A.

FIG. 11C is an enlarged detail view of FIG. 8 taken along the curve 11Cin FIG. 8.

FIG. 11D is an enlarged detail view of FIG. 8 taken along the curve 11Din FIG. 8.

FIG. 12A is a schematic representation of the dual concentric guidewireassembly of the embodiment of the deployment catheter shown in FIG. 3,showing the position of the main branch restraint member and thecontralateral branch restraint member before deployment of the mainbranch of the graft.

FIG. 12B is an enlarged detail view of FIG. 12A taken along the curve12B in FIG. 12A.

FIG. 12C is a schematic representation of the dual concentric guidewireassembly (or guidewire sheath) of the embodiment of the deploymentcatheter shown in FIG. 3, showing the position of the main branchrestraint member and the contralateral branch restraint member afterdeployment of the main branch portion of the graft.

FIG. 13 is a schematic representation of an embodiment of the deploymentcatheter with the guidewire sheath positioned across the bifurcation.

FIG. 14 is a schematic representation, as in FIG. 13, with thedeployment catheter positioned in the aorta.

FIG. 15 is a schematic representation, as in FIG. 14, with thecompressed iliac branches of the graft positioned partly within theiliac arteries.

FIG. 16 is a schematic representation, as in FIG. 14, with thecompressed iliac branches of the graft positioned substantially entirelywithin the iliac arteries.

FIG. 17 is a schematic representation, as in FIG. 16, with a proximalportion of the main branch portion of the graft at least partiallydeployed within the aorta.

FIG. 18 is a schematic representation, as in FIG. 17, with a proximalportion and a distal portion of the main branch portion of the graftpartially deployed within the aorta.

FIG. 19 is a schematic representation, as in FIG. 17, followingdeployment of substantially the entire length of the main branch portionof the graft within the aorta.

FIG. 20 is a schematic representation, as in FIG. 19, following thepartial retraction of the guidewire sheath and the main graft sheaththrough the contralateral iliac artery.

FIG. 21 is a schematic representation, as in FIG. 20, following thefurther proximal retraction of the guidewire sheath and thecontralateral branch sheath through the contralateral iliac artery,causing the deployment of the contralateral branch portion of the graft.

FIG. 22 is a schematic representation, as in FIG. 21, following theproximal retraction of the ipsilateral branch sheath and deployment ofthe ipsilateral branch portion of the graft.

FIG. 23 is a schematic representation, as in FIG. 22, of the deployedbifurcated graft with the inner core wire positioned within the mainbranch portion of the deployed graft.

DETAILED DESCRIPTION OF SOME EXEMPLIFYING EMBODIMENTS

The following detailed description is now directed to certain specificembodiments of the disclosure. In this description, reference is made tothe figures wherein like parts are designated with like numeralsthroughout the description and the drawings. Described below are variousembodiments of a delivery system for deploying a vascular graftincluding a deployment catheter and a hollow guidewire assembly whichmay be used to maintain access through an implanted vascular graft forsubsequent catheterizations.

Endoluminal repair or exclusion of aortic aneurysms has been performedfor the past several years. The goal of endoluminal aortic aneurysmexclusion has been to correct this life threatening disease in aminimally invasive manner in order to effectuate a patient's quick andcomplete recovery. Various vascular grafts exist in the prior art thathave been used to exclude aortic aneurysms. In general, transluminallyimplantable prostheses adapted for use in the abdominal aorta comprise atubular wire cage surrounded by a tubular PTFE or Dacron sleeve. Bothballoon expandable and self-expandable support structures may be used tosupport the tubular sleeve. Without limitation, the deployment systemdisclosed herein can be used to deliver both straight and bifurcatedendovascular prostheses adapted to treat both straight segment andbifurcated segment aneurysms.

Endoluminal implantation is an increasingly accepted technique forimplanting vascular grafts. Typically, this procedure involvespercutaneously inserting a vascular graft or prosthesis by using adelivery catheter. This process eliminates the need for major surgicalintervention, thereby decreasing the risks associated with vascular andarterial surgery. Various embodiments of catheter delivery systems forprosthetic devices are described herein.

Certain current delivery systems for a bifurcated stent graft system ora graft having at least one branch portion may use two sheaths moving inopposing directions to deploy the distal segment of the graft before theproximal segment. The outer sheath is first retracted to deploy aportion of the mid-body and the contralateral limb. Then, the frontsheath is advanced distally to deploy the distal end of the graft. Seee.g., U.S. Pat. No. 6,660,030. Other delivery systems, for example asdisclosed in U.S. patent application Ser. No. 11/522,292, titled “AMULTI-SEGMENTED GRAFT DEPLOYMENT SYSTEM” and filed on Sep. 15, 2006 (theentirety of which is hereby incorporated by reference as if fully setforth herein) may use a plurality of axially spaced releasable restraintmembers temporarily connected by a pull wire to allow the distal mainbranch portion to be deployed before a proximal graft portion.Typically, these delivery systems are delivered to the aneurysm locationover a guidewire. The guidewire may be further used to release a branchgraft portion of the prosthesis, for example, by operably connecting abranch graft restraint mechanism to the guidewire and proximallywithdrawing the guidewire from the vasculature.

Once the bifurcation graft has been deployed and implanted, a variety ofprocedures may desirably be accomplished. For example, it may beadvantageous to implant a cuff on the proximal end of the main branchportion to secure the graft and thereby prevent movement or slippage ofthe main branch portion. Alternatively, it may be necessary to dilatethe stenosis or touch up or re-establish the expansion of the graft.These procedures require advancing another catheter to the graftlocation along a guidewire. However, the positioning of a guidewirethrough the graft after the graft has been deployed is difficult sincethe tip of the guidewire will snag on the wire support cage of thegraft. Thus, it may be advantageous to provide a guidewire assemblyconfigured to remain placed through a graft once the graft has beendeployed and to allow access through the expanded graft for subsequentcatheterizations. Additionally, it may be advantageous to improve theconfiguration of the deployment catheter and/or the graft restrainingmembers so as to improve the methods of deploying and positioningbifurcated and non-bifurcated grafts, as will be described herein.

As used herein, the relative terms “proximal” and “distal” shall bedefined from the perspective of the delivery system. Thus, proximalrefers to the direction of the control end of the delivery system anddistal refers to the direction of the distal tip. In certainembodiments, the deployment catheter may be configured to deliver agraft that includes a main or distal graft portion and at least onebranch or proximal graft portion. In certain embodiments, the hollowguidewire assembly may be associated with a restraint member for thebranch segment, such that the branch segment may be deployed by theguidewire assembly. The guidewire assembly may be further configuredsuch that it may be used to remove the restraint member from the branchsegment while permitting placement and maintenance of a guidewirethrough the expanded branch segment and main body graft for subsequentcatheterizations. Other embodiments of a graft deployment system andguidewire assembly will also be described below.

FIG. 1A is a schematic representation of an example of a bifurcatedvascular prosthesis 50 that can be used with any embodiment of thedeployment catheter disclosed herein, positioned at the bifurcationbetween the abdominal aorta and the right and left common iliacarteries. With reference to FIG. 1A, there is illustrated a schematicrepresentation of the abdominal part of the aorta and its principalbranches. In particular, the abdominal aorta 30 is characterized by aright renal artery 2 and left renal artery 4. The large terminalbranches of the aorta 30 are the right and left common iliac arteries 37and 38. Additional vessels (e.g., second lumbar, testicular, inferiormesenteric, middle sacral) have been omitted from FIG. 1A forsimplification. One embodiment of an expanded bifurcated endoluminalvascular prosthesis is shown spanning aneurysms 103, 104 and 105. Theexpanded bifurcated endoluminal vascular prosthesis 50 can comprise amain branch portion 52 (also referred to herein as a main branchsegment) for traversing the aorta, a first branch portion 54 (alsoreferred to herein as a first branch segment or an ipsilateral branchportion) for spanning an ipsilateral iliac artery 37, and a secondbranch portion 56 (also referred to herein as a second branch segment ora contralateral branch portion) for spanning a contralateral iliacartery 38.

Note that the terms “first” and “second” branch portion can be usedinterchangeably and to refer to any branch vessel in the body, includingbut not limited to the ipsilateral vessel, the contralateral vessel,radial vessels, and subclavian vessels. Accordingly, in someembodiments, the “first” branch portion can refer to any branch portionincluding but not limited to the vessels set forth above. Similarly, the“second” branch portion can refer to any branch portion including butnot limited to the vessels set forth above. In one embodiment, the firstbranch portion can refer to a downstream or upstream portion of a mainbranch vessel. For example, in one embodiment, the main branch portionand the first branch portion are configured to lie within at least aportion aortic arch (including, for example, the ascending and/ordescending aorta) with main branch portion positioned closer to theheart while the second branch portion can be configured to extend intoone of the branch vessels (left subclavian, right subclavian or carotid)that extend from the aortic arch.

FIG. 1B is an exploded view of the bifurcated prosthesis 50 of FIG. 1A,which can include a preferably self-expanding wire support cage 60 andan outer polymeric sleeve 68. In FIG. 1B, the wire support 60 is shownseparated from an outer polymeric sleeve 68. In the illustratedembodiment, the polymeric sleeve 68 can be situated concentricallyoutside of the tubular wire support 60. However, other embodiments mayinclude a sleeve positioned instead concentrically inside the wiresupport or positioned on both the inside and the outside of the wiresupport. Alternatively, the wire support may be embedded within apolymeric matrix or layer which makes up the sleeve. The sleeve 68 maybe attached to the wire support 60 by any of a variety of suitablemanners known to those skilled in the art.

The tubular wire support 60 can comprise a main branch portion 62 fortraversing the aorta, a first branch portion 64 (also referred to hereinas an ipsilateral branch portion) for spanning an ipsilateral iliac anda second branch portion 66 (also referred to herein as a contralateralbranch portion) for spanning a contralateral iliac. The main branchportion 62 and first ipsilateral branch portion 64 can be formed from acontinuous single length of wire having a proximal end, a distal end anda central lumen extending therebetween. Alternatively, the firstipsilateral branch portion 64 may be formed of one or more lengths ofwire pivotably connected to the proximal end of the main branch portion62. A second, contralateral branch component 66 may be formed of one ormore lengths of wire pivotably connected to the proximal end of the mainbranch portion 62. Each of the iliac branch components has a proximalend, a distal end and a central lumen extending therethrough.Construction of the graft from a three part cage convenientlyfacilitates the use of different gauge wire in the different components(e.g. 0.014 in. diameter main trunk and 0.012 in. diameter branchcomponents).

In general, each of the components of the bifurcated endoluminalvascular prosthesis 50 may vary considerably in diameter, length,expansion coefficient, and other parameters or characteristics,depending upon the intended application. For implantation within theaorta of a typical adult, the main branch portion 52 will have a lengthwithin the range of from approximately 2 in. or less to approximately 5in. or more, and, typically within the range of from approximately 3.5in. to approximately 4 in. The unconstrained outside expanded diameterof the main branch portion 52 will typically be within the range of fromapproximately 0.75 in. to approximately 1.5 in. The unconstrainedexpanded outside diameter of the main branch portion 52 can be constantor substantially constant throughout the length, or can be tapered froma relatively larger diameter at the distal end to a relatively smallerdiameter at the bifurcation. In general, the diameter of the proximalend of the main branch portion will be on the order of no more thanapproximately 95% and, preferably, no more than approximately 85% of thediameter of the distal end of the main branch portion. The iliac branchportions 54 and 56 will typically be bilaterally symmetrical, having alength within the range of from approximately 0.4 in. to approximately2.6 in., and a diameter within the range of from approximately 0.04 in.to approximately 0.79 in.

The collapsed prosthesis for use in accordance with the presentdisclosure has a diameter in the range of approximately 0.08 in. toapproximately 0.39 in. Preferably, the maximum diameter of the collapsedprosthesis is in the range of approximately 0.12 in. to approximately0.24 in. (12 to 18 French). Some embodiments of the deployment catheter,including the prosthesis, can have a diameter in the range of fromapproximately 18 to approximately 20 or approximately 21 French. Otherembodiments can have a diameter as low as approximately 19 French,approximately 16 French, approximately 14 French, or smaller. Afterdeployment, the expanded endoluminal vascular prosthesis may radiallyself-expand to a diameter anywhere in the range of approximately 0.8 in.to approximately 1.6 in.

Although certain prosthesis configurations are disclosed herein, theseare only examples of prostheses which are deployable using theembodiments of a deployment catheter and guidewire assembly describedherein. In other embodiments, the delivery system described below may beused to deliver and deploy other types of self-expandable bifurcated ormulti-segmented prosthesis having a main branch portion and at least onebranch graft portion, as will be apparent to those of skill in the artin view of the disclosure herein. For example, in other embodiments,certain features and aspects of the deployment catheter and guidewireassembly can be used to deploy a graft without a branch graft portion, agraft with only one branch portion and/or a graft with more than onegraft portions. Further details and additional embodiments of theprosthesis described above can be found in U.S. Pat. Nos. 6,007,296,6,187,036, and 6,197,049, the entirety of which are hereby incorporatedby reference herein.

It should also be appreciated that, although the illustrated embodimentsare described in the context of a bifurcated graft configured for theabdominal aorta, certain features and aspects of the delivery systemsand methods described herein can be used in other portions of thevascular system. For example, it is anticipated that certain featuresand aspects of the systems and methods described herein can be adaptedfor use in the thoracic aorta. Accordingly, in some embodiments, thedeployment catheter 120 may be configured to treat defects that mayinclude, but are not limited to, abdominal aortic aneurysms, subclaviananeurysms, and thoracic aortic aneurysms, to name a few. It is alsoanticipated that certain features and aspects of the system describedherein may be adapted to deliver a single straight graft segment to thethoracic aorta or other vessels or arteries within the body.

The self-expandable bifurcation graft can be deployed at a treatmentsite with any of a variety of deployment catheters, as will be apparentto those of skill in the art. Any of the embodiments of the deploymentcatheters disclosed herein may comprise any of the materials, features,or other details of any deployment catheters suitable for deploying aself-expanding bifurcation graft known in the field, or in any of theembodiments disclosed in U.S. Pat. No. 6,090,128, U.S. Pat. No.6,500,202, U.S. Pat. No. 6,660,030, U.S. patent application Ser. No.11/522,292, titled “A MULTI-SEGMENTED GRAFT DEPLOYMENT SYSTEM” and filedon Sep. 15, 2006, and in U.S. patent application Ser. No. 11/623022,titled “DUAL CONCENTRIC GUIDEWIRE AND METHODS OF BIFURCATED GRAFTDEPLOYMENT” and filed on Jan. 12, 2007. The entirety of theabove-referenced patents and patent applications are hereby incorporatedby reference in their entirety as if fully set forth herein.

With reference to FIG. 2, one method for using an embodiment of thedeployment catheter 120 for treating an abdominal aortic aneurysm willbe briefly described, without limitation. More detail regarding thisdeployment method will be described below. FIG. 2 is a schematicrepresentation of an embodiment of a deployment catheter 120 fordelivering a bifurcated prosthesis or graft 178, showing a proximalportion of the main branch portion 180 of the graft 178 at leastpartially deployed within the aorta for illustration purposes. As shownin FIG. 2, the deployment catheter 120 has preferably been introducedinto a patient's vasculature through a puncture site in the patient'sipsilateral artery. The deployment catheter 120 is not limited totreatment of an abdominal aortic aneurysm, it can be configured to treatother aneurysms as discussed more fully herein. Additionally, dependingon the clinical requirements, the deployment catheter 120 can beintroduced into the patient's vasculature through puncture sites otherthan the ipsilateral artery. For example, without limitation, thedeployment catheter 120 can be introduced into the patient's vasculaturethrough the contralateral artery, through the radial artery, or throughthe subclavian artery.

As illustrated in FIG. 2, the deployment catheter 120 has preferablybeen advanced over a guidewire 226 to the desired location within thepatient's aorta. The graft 178 illustrated in FIG. 2 preferablycomprises a main branch portion 180 constrained within a main branchsheath or member 186, an ipsilateral branch portion 182 constrainedwithin and ipsilateral branch sheath or member 188, and a contralateralbranch portion 184 constrained within a contralateral branch sheath ormember 190. Prior to the deployment of the main branch portion 180 ofthe graft 178 as shown in FIG. 2, the entire graft was preferablyconstrained within an outer sheath 128 of the deployment catheter 120.In brief, the graft 178 was exposed by retracting the outer sheath 128,and the deployment catheter 120 was manipulated so as to position thecontralateral branch portion 184 in the contralateral artery 38.

After positioning the graft 178 in the desired position, illustrated inFIG. 2, the main branch portion 180 of the graft 178 was deployed byretracting a sheath release wire 166, which caused the perforated mainbranch sheath 186 to tear along a side thereof. The remaining portion ofthe main branch portion 180 will preferably be deployed by furtherwithdrawing the sheath release wire 166. In the illustrated embodiment,the contralateral branch portion 184 of the graft 178 will preferably bedeployed by withdrawing the guidewire sheath 216 through a puncture sitein the contralateral iliac artery 38, causing the contralateral branchsheath 190 to be withdrawn. The main branch sheath 186 is preferablyalso connected to the contralateral guidewire sheath 216 and ispreferably withdrawn with the contralateral branch sheath 190.Similarly, in the final step in the deployment of the graft 178, theipsilateral branch portion 182 of the graft 178 will preferably bedeployed by withdrawing the deployment catheter 120 through a puncturesite in the ipsilateral iliac artery 37, causing the ipsilateral branchsheath 188 to be withdrawn.

The deployment method described with reference to FIG. 2 is not intendedto limit the applicability of the deployment catheter 120. Thedeployment catheter described herein may be configured to deploy astraight, bifurcated, or any other graft configuration into any portionof an artery or other blood vessel in the body. In some embodiments, thedeployment catheter 120 may be used to deploy grafts having anchoringelements that help secure the graft to the vessel wall as well as graftsthat do not have anchoring elements. With this brief, non-limitingoverview of one method of using the deployment catheter 120 having beendescribed, additional features and configurations of the deploymentcatheter 120 and additional details of this and other deployment methodswill now be described.

FIG. 3 is a cross-sectional view of an embodiment of a deploymentcatheter 120 for delivering a bifurcated vascular prosthesis, such asbut not limited to the prosthesis 50 described above. The deploymentcatheter 120 preferably comprises an elongate flexible, multi-componenttubular body 122 having a proximal end 124 and a distal end 126. Thetubular body 122 and other components of this system can be manufacturedin accordance with any of a variety of techniques well known in thecatheter manufacturing field. Suitable materials and dimensions can bereadily selected taking into account the natural anatomical dimensionsin the iliacs and aorta, together with the dimensions of the desiredpercutaneous access site.

In some embodiments, the elongate flexible tubular body 122 preferablycomprises an outer sheath 128 that is preferably supported by a valvemember 130. In the illustrated embodiment, the outer sheath 128 ispreferably axially and radially supported by the valve member 130 sothat the outer sheath 128 and valve member 130 translate and rotate inunison so that the rotation or translation of the mammoth old 130preferably causes commensurate rotation or translation of the outersheath 128. The tubular body 122 preferably also comprises a centralinner core 132 that is preferably supported within the outer sheath 128so as to be axially moveable within the outer sheath 128. Additionally,in some embodiments, as in the illustrated embodiment, a support sleeve136 may be positioned adjacent to the valve member 130 and adhered orotherwise attached to the outside of the outer sheath 128 to provideadditional stiffness or support to the outer sheath 128 adjacent to thevalve member 130.

As mentioned above, the outer sheath 128 can comprise a valve member 130at the proximal end of the outer sheath 128. In some embodiments, thevalve member 130 preferably has a hemostatic valve 134 that can providean access port for the infusion of drugs or contrast media as will beunderstood by those of skill in the art. In some embodiments, the outertubular sheath 128 preferably comprises extruded PTFE, having an outsidediameter of approximately 0.250 in. and an inside diameter ofapproximately 0.230 in. in some embodiments, the outer sheath 128 canhave an outside diameter of between approximately 18 French andapproximately 22 French. In some embodiments, the outer sheath 128 canbe formed from PEBAX, nylon, polyethylene, or any other material that issuitable for endovascular delivery systems. In some embodiments, theouter sheath 128 is preferably a thin-walled, collapsible sheath. Insome embodiments, the outer sheath 128 can comprise an inner liner, anouter layer, and an embedded metal braid or metal wire coil. In someembodiments, the inner liner can be comprised from PTFE or any othersuitable material that preferably provides a low friction surface forpassage of the inner core 132. The outer layer preferably formed from asoft, thin-walled plastic such as PEBAX, but can be made from any othersuitable material. The outer layer is preferably formed from a materialthat is soft enough to permit the lumen of the outer sheath 128 toreopen after a kink or constriction has been formed in the outer sheath128.

In some embodiments, the outer sheath 128 can be reinforced with a metalcoil instead of the metal braid. The metal braid or coil can be formedfrom stainless steel, nitinol, or any other suitable material including,but not limited to, shape memory materials. In some embodiments, thesheath 128 preferably has sufficient memory to recoil from a collapsedposition into a patent position such that any kinks in the outer sheath128 are easily opened when the inner core 132, or other diagnostic ortherapeutic catheter based devices known to the art, is passed throughthe outer sheath 128. As such, only a small force is preferably requiredto pass the inner core 132 through any portions of the outer sheath 128that have become kinked or collapsed. In this configuration, the outersheath 128 preferably provides a patent lumen suitable for highlytortuous anatomies where traditional outer sheath materials may kink orcollapse.

In some embodiments, the liner preferably has a wall thickness less thanor equal to approximately 0.002 in. However, in some embodiments, theliner can have a wall thickness from approximately 0.001 in. or less toapproximately 0.003 in., or from approximately 0.003 in. toapproximately 0.005 in. or more. In some embodiments, the metal braid orcoil preferably has a thickness of less than or equal to approximately0.002 in. However, in some embodiments, the metal braid or coil can havea wall thickness from approximately 0.001 in. or less to approximately0.003 in., or from approximately 0.003 in. to approximately 0.005 in. ormore. In some embodiments, the outer layer preferably has a wallthickness less than or equal to approximately 0.01 in. and a Durometerhardness value less than or equal to approximately 72 D. However, insome embodiments, the outer layer can have a wall thickness fromapproximately 0.005 in. to approximately 0.008 in., or fromapproximately 0.008 in. to approximately 0.011 in. or more, and aDurometer hardness value from approximately 55 D or less toapproximately 65 D, or from approximately 65 D to approximately 75 D ormore. However, the thickness, dimension, shape, hardness, and otheraspects of the configurations of each of the materials comprising theouter sheath 128 are not limited to those described herein, but can beof any thickness, dimension, shape, or hardness suitable forendovascular delivery systems.

In some embodiments, the outer tubular sheath 128 preferably has anaxial length within the range of from approximately 15 in. or less toapproximately 22 in. or more. In one embodiment of the deploymentcatheter 120 having an overall length of 33 in., the axial length of theouter tubular sheath 128 is preferably approximately 15 in. and theoutside diameter is preferably less than or equal to approximately 0.28in. In some embodiments, the distal end 128 a of the tubular sheath 128may be located at least approximately 2 in. from the distal end of thedistal tip 174 of the deployment catheter 120, in a prosthesis loadedconfiguration.

In some embodiments, as in the illustrated embodiment, the central innercore 132 is preferably axially and rotatably movable within the outersheath 128. However, in some embodiments, the central inner core 132 maybe rotationally fixed relative to the outer sheath 128. Rotationalengagement can be accomplished in any of a variety of ways, normallyinvolving complementary surface structures such as keys or splines onthe associated components. For example, the central inner core 132 canbe provided with a radially outwardly extending projection along aportion or all of its axial length. This projection would preferably beslidably received within a radially outwardly extending slot on theinterior surface of the outer sheath 128. Alternatively, a radiallyinwardly extending projection on the outer sheath 128 or associatedcomponent can be received with an axially extending recess on the outersurface of the central inner core 132. Alternatively, any of a varietyof non-round configurations for the central inner core 132 such aselliptical, ovular, triangular, square, polygonal, circular with flatsides, and the like, can be slidably received within acomplementary-shaped aperture on or connected to the outer sheath 128.

Alternatively, in some embodiments the inner core 132 and the valvemember 130 may define complementary flat surfaces or other features suchas, but not limited to, those described above that prevent the innercore 132 from rotating relative to the valve member 130, while the innerlumen of the outer sheath 128 may be circular. Additionally, in someembodiments, the valve member 130 may be tightened around the outersurface of the inner core 132 so as to substantially prevent the innercore 132 from translating and/or rotating relative to the valve member130.

FIG. 3A is cross-sectional view of the illustrated embodiment of thedeployment catheter 120 taken along line 3A-3A of FIG. 3. As showntherein, in the illustrated embodiment, the cross-section of the centralinner core 132 is preferably circular. However, in some embodiments asmentioned above, the cross-section of the central inner core 132 candeviate from a circular cross-section by the provision of one or twoopposing flat sides extending axially along the length of the inner core132. In the embodiments where the cross-section of the central innercore 132 deviates from a circular cross-section, an aperture with acorresponding cross-section may be provided in the outer sheath 128and/or the valve member 130 such that the rotation of the outer sheath128 or the valve member 130 will preferably cause a similar rotation ofthe central inner core 132.

With reference to FIGS. 3 and 3A, the inner core preferably comprises aguidewire lumen 154 and a sheath release lumen 156 extendinglongitudinally therethrough. In the illustrated embodiment, theguidewire lumen 154 preferably extends throughout the entire length ofthe tubular central core 132, having a distal exit port 158 and aproximal access port 160, as will be understood by those of skill in theart. In use, the deployment catheter 120 will preferably be advancedinto position in the aorta over a guidewire extending through theguidewire lumen 154, as will be understood by those of skill in the art.A sheath release wire 166 (also referred to herein as a suture), whichwill be described in greater detail below, is preferably routed throughthe sheath release lumen 156. In the illustrated embodiment, the sheathrelease lumen 156 preferably extends through the entire length of thetubular central core 132, having a distal exit port 162 (shown mostclearly in FIG. 4) and a proximal access port 164 (shown most clearly inFIG. 3), as will be understood by those of skill in the art.

In the embodiment of the deployment catheter 120 illustrated in FIG. 3A,the guidewire lumen 154 is preferably co-planar with the centerline axisof the inner core 132 and the sheath release lumen 156. However, thisarrangement is not required. In some embodiments, as illustrated in FIG.3B, which is a cross-sectional view of an alternative of the embodimentof the deployment catheter 120 shown in FIG. 3 taken along line 3B-3B ofFIG. 3, the guidewire lumen 154 is preferably not coplanar with thecenterline axis of the inner core 132 and the sheath release lumen 156.Therefore, as illustrated in FIG. 3B, the inner core 132 may beconfigured so that the guidewire lumen 154 and the sheath release lumen156 are formed at any desired position in the cross-section of the innercore 132.

In the illustrated embodiment, the sheath release wire 166 is preferablyattached to a tabbed handle 167 that is supported by a “Y” connector169. In some embodiments, the handle 167 is configured to enable theuser or medical practitioner to manipulate the sheath release wire 166.In some embodiments, the handle 167 is preferably removable from the “Y”connector 169 so that the medical practitioner or user can manipulatethe handle 167 and, hence, the sheath release wire 166, independent ofthe “Y” connector 169. In some embodiments, the handle 167 may bethreadedly and, hence, removably supported by the “Y” connector 169. Insome embodiments, the handle 167 may be attached to, but configured tobreak away from, the “Y” connector 169 when the user or medicalpractitioner exerts a threshold force or to work on the handle 167relative to the “Y” connector 169. In some embodiments, the handle 167may be press fit into a complementary opening in the “Y” connector 169so that the medical practitioner or user may remove the handle 167 fromthe “Y” connector 169 by pulling and/or turning the handle 167 relativeto the “Y” connector 169.

The sheath release wire 166 preferably passes through a first port 169 ain the “Y” connector 169 and so on through the sheath release lumen 156as described above. The guidewire discussed above that can extendthrough the central guidewire lumen 154 can pass through a second port169 b in the “Y” connector 169. The “Y” connector 169 is preferablysecured to the proximal end of the inner core 132 such as by thermalbonding, adhesive bonding, and/or any of a variety of other securingtechniques known in the art.

An interface member 168 is preferably secured to the distal end of theinner core 132 such as by thermal bonding, adhesive bonding, and/or anyof a variety of other securing techniques known in the art. Theinterface member 168 is preferably axially and rotationally secured tothe inner core 132. The interface member 168 preferably axially androtationally supports a central tube 170 so that the central tube 170preferably cannot substantially rotate or translate axially relative tothe inner core 132. In the illustrated embodiment, the central tube 170preferably defines a lumen axially therethrough that is preferablyaxially aligned with the guidewire lumen 154 so that a guidewire that isadvanced through the guidewire lumen 154 can also be advanced throughthe lumen of the central tube 170. A wire support 172 is preferablyattached to the outside of the central tube 170 and supported by theinterface member 168 to provide additional support to the central tube170.

The tubing 170 may be formed from any suitable plastic or metalmaterial, such as but not limited to stainless steel or nitinol, or anyother material that is suitable for endovascular delivery systems. Insome embodiments, the tubing 170 is preferably formed of braided metalso as to provide flexibility, tensile strength, and torsional strength.In some embodiments, the tubing 170 may be formed from multiplematerials, including but not limited to being formed of a braided metalouter sheath that is lined with a plastic or other suitable material forsupport and/or to reduce frictional forces from a guidewire advancedtherethrough.

A distal segment of the deployment catheter 120 preferably comprises anelongate, flexible tapered distal tip 174. In the illustratedembodiment, the distal tip 174 is preferably supported by the centraltube 170. The distal tip 174 may over molded onto an anchor 176 that issecured to the outside surface of the central tube 170. Thus, in theillustrated embodiment, the distal tip 174 is preferably axially androtationally supported on the central tube 170 so that the distal tip174 is substantially prevented from any axial movement or rotationrelative to the central tube 170. The central tube 170 is preferablyconfigured to define a longitudinal opening therethrough, thelongitudinal opening or lumen being preferably axially aligned with theguidewire lumen 154 such that a guidewire extending through theguidewire lumen 154 can also extend through the lumen in the centraltube 170.

In the illustrated embodiment, the central tube 170 preferably protrudesinto the distal tip 174 to a short distance beyond the location of theanchor 176. In some embodiments, however, at least a portion of theanchor 176 may extend all the way to the end of the distal tip 174, orbeyond. In the illustrated embodiment, an aperture or opening 177 in thedistal tip 174 is preferably axially aligned with the opening in thecentral tube 170, such that a guidewire passing through the opening inthe central tube 170 may also pass through the opening 177 in the distaltip 174. In this configuration, the distal tip 174 is preferablysubstantially axially and rotationally fixed to the inner core 132 suchthat the axial and rotational positioning of the distal tip 174 can becontrolled by the axial and rotational positioning of the inner core132.

With reference to FIG. 3, the distal tip 174 preferably tapers from anoutside diameter of approximately 0.225 in. at its proximal end to anoutside diameter of approximately 0.070 in. at the distal end thereof.In some embodiments, the overall length of the distal tip 174 isapproximately 2.5 in. However, the length and rate of taper of thedistal tip 174 can be varied depending upon the desired trackability andflexibility characteristics, as well as other factors.

FIG. 4 is an enlargement of the portion delineated by the curve 4 inFIG. 3. FIGS. 5 and 6 are a cross-sectional view of the embodiment ofthe deployment catheter shown in FIG. 3 taken along line 5-5 and line6-6, respectively, of FIG. 4. With reference to FIGS. 4-6, a bifurcatedendoluminal graft 178 is illustrated in a compressed configurationwithin the deployment catheter 120, prior to the advancement of theinner core 132 relative to the other sheath 128. The graft 178preferably comprises a distal aortic trunk or main branch portion 180, aproximal ipsilateral branch portion 182, and a proximal contralateraliliac portion 156. In the illustrated embodiment, the aortic main branchportion 180 of the graft 178 is preferably constrained within a mainbranch sheath 186. While the embodiment of main branch sheath 186 isshown with reference to compressing a main branch graft portion 180, itis envisioned that the sheath 186 could alternatively be used tocompress and deliver other portions of a multi-segmented vascular graft,such as a branch graft portion, the entire multi-segmented graft, or asingle-segment, straight vascular graft. Further, in the illustratedembodiment, the ipsilateral branch portion 182 is preferably constrainedwith a preferably tubular ipsilateral branch sheath 188 (also referredto herein as the first branch sheath), and the contralateral branchportion 184 (also referred to herein as the second branch sheath) ispreferably constrained within a preferably generally tubularcontralateral branch sheath 190. In the illustrated embodiment, theipsilateral branch sheath 188 and the contralateral branch sheath 190are preferably open-ended tubular sheaths.

The ipsilateral branch sheath 188 preferably constrains substantiallythe entire length of the ipsilateral branch portion 182 of thebifurcated graft 178. Similarly, in the illustrated embodiment, thecontralateral branch sheath 190 preferably constrains substantially theentire length of the contralateral branch portion 184 and of thebifurcated graft 178. However, in some embodiments, the ipsilateralbranch sheath 188 and/or the contralateral branch sheath 190 mayconstrain substantially more or less than the entire length of theipsilateral branch portion 182 or the contralateral branch portion 184,respectively, of the bifurcated graft 178.

With reference to FIG. 4, the main branch sheath 186 can be sized andconfigured to cover the entire length of the bifurcated graft 178.However, in some embodiments, the main branch sheath 186 is preferablyconfigured to constrain only the length of the main branch portion 180of the bifurcated graft 178. Thus, even though the main branch sheath186 may extend to the distal end of the contralateral branch portion 184of the graft 178, in some embodiments, the main branch sheath 186 ispreferably configured so as to define a notch 192 along the portion ofthe length of the main branch sheath 186 that covers the contralateralbranch portion 184. In some embodiments, the notch 192 can be a slitalong a portion of the length of the main branch sheath 186. In someembodiments, as in the illustrated embodiment, the notch 192 preferablyremoves a portion of the main branch sheath 186 along a portion of thelength of the main branch sheath 186 that can be less than or equal toapproximately half of the perimeter of the main branch sheath 186. Insome embodiments, the main branch sheath 186 can be skived to remove asuitable amount of the material comprising the main branch sheath 186 toallow the ipsilateral or contralateral branch portion 182, 184 of thegraft 178 to deploy upon retraction of the outer sheath 128. Thus, insome embodiments, the main branch sheath 186 preferably does notconstrain the ipsilateral or contralateral branch portion 182, 184 ofthe bifurcated endoluminal graft 178.

In some embodiments, as illustrated in FIG. 4, a torsion tab 196 ispreferably integrally formed with the central tube 170, or securedthereto such as by thermal bonding, adhesive bonding, and/or any of avariety of other securing techniques known in the art. As isillustrated, the main branch portion 180 of the bifurcated endoluminalgraft 178 is preferably constrained by the main branch sheath 186 aroundthe torsion tab 196. In the illustrated embodiment, the torsion tab 196preferably engages with the endoskeleton or, with reference to FIG. 1B,the wire support cage 60 of the bifurcated graft 178 and ensures thatthe bifurcated graft 178 substantially rotates with the inner core 132of the deployment catheter 120. In other words, the torsion tab 196preferably prevents the central tube 170 from rotating relative to thebifurcated graft 178. This preferably enhances the ability of themedical practitioner or user to rotate and, hence, maneuver, the graft178 and the ipsilateral and/or contralateral branch portions 182, 184within the patient's aorta by rotating the proximal end of thedeployment catheter 120, in particular, by rotating the proximal end ofthe inner core 132 or the “Y” connector 169. As such, the torsion tab196 preferably causes of the bifurcated endoluminal graft 178 to rotatesubstantially in unison with the central tube 170.

As will be discussed in greater detail, in some embodiments such as inthe illustrated embodiment, the main branch sheath 186 will preferablybe retracted through the contralateral iliac artery using acontralateral guidewire 194 after the main branch portion 180 of thebifurcated endoluminal graft 178 has been deployed. In some embodiments,the contralateral guidewire 194 preferably defines a lumenlongitudinally therethrough, so that a smaller diameter guidewire can beadvanced therethrough. Additionally, in some embodiments, thecontralateral branch sheath 190 will preferably be deployed using thecontralateral guidewire 194. The contralateral guidewire 194 and theconstricted end portion 186 a of the main branch sheath 186 arepreferably configured so that the contralateral guidewire 194 issubstantially permitted to slide through the opening in the constrictedend portion 186 a of the main branch sheath 186 while stops or tabspositioned on the guidewire 194 are prevented from sliding throughconstricted portion 186 a.

Accordingly, in the illustrated embodiment, a tab 198 is preferablyattached to the outside surface of the contralateral guidewire 194 suchas by thermal bonding, adhesive bonding, and/or any of a variety ofother securing techniques known in the art. The tab 198 is preferablypositioned and configured such that, as the contralateral guidewire 194slides through the end portion 186 a of the main branch sheath 186, thetab 198 is prevented from sliding through the constricted opening in theend portion 186 a of the main branch sheath 186. In this arrangement,with the main graft tab 198 abutted against the constricted end portion186 a of the main branch portion graft 186, as the contralateralguidewire 194 is further retracted through the contralateral iliacartery, the main graft tab 198 will cause the main branch sheath 186 toalso be retracted through the contralateral iliac artery. Additionally,a contralateral graft tab 200 is preferably positioned near to, orapproximately adjacent to, the first end 194 a of the contralateralguidewire 194 to engage and retract the contralateral branch sheath 190,as described in more detail below.

In the illustrated embodiment, the contralateral guidewire 194 ispreferably approximately 160 cm. (63 in.) in length. In someembodiments, the contralateral guidewire 194 can be approximately 170cm. (67 in.), or approximately 180 cm. (71 in.). Because thecontralateral guidewire 194 is preferably positioned within orintegrated into the deployment catheter 120 in the pre-deployment state,the contralateral guidewire 194 is preferably shorter than theconventional guidewires (e.g., the typical 300 cm. exchange lengthguidewires) that were typically inserted by the medical practitionerinto a catheter for gaining access to, for example, the thoracic aorticregion. In this configuration, a 0.014 in. guidewire may be advancedthrough the contralateral guidewire 194 and into the deep thoracicaortic region before (or after) the main branch portion 180 of the graft178 is deployed. However, in any of the embodiments disclosed herein,the contralateral guidewire 194 may be configured so that a 0.018 in, ora 0.035 in., or any other suitable guidewire may be advancedtherethrough. Accordingly, because the length of the contralateralguidewire 194 of this configuration can be short as 160 cm., the 0.014in. guidewire that may be advanced through the contralateral guidewire194 may similarly have a shorter length than the conventional guidewiresthat were used for this purpose. In the illustrated embodiment, a 0.014in. guidewire having a length of approximately 180 cm. (71 in.) or 190cm. (75 in.) may be used. However, the contralateral guidewire 194 andother guidewires disclosed herein can be formed in any suitable lengthsand are not restricted to the dimensions disclosed herein.

The contralateral guidewire 194 preferably defines a first end (or alsoreferred to as a distal end) 194 a, as shown most clearly in FIG. 8, anda second end (or also referred to as a proximal end) 194 b. In theillustrated embodiment, the second and 194 b can be advanced through apuncture site in the patient's vasculature so that, when the deliverydevice 120 is positioned within the patient's vasculature, the secondend 194 b of the contralateral guidewire 194 is located outside of thepatient's body and, hence, directly accessible by the medicalpractitioner or user. In some embodiments, as illustrated in FIG. 3,after the contralateral guidewire 194 passes away from the distal tip174 through the main branch portion 180 and the branch portion 184 ofthe bifurcated graft 178, the guidewire 194 is preferably looped backaround within the outer sheath 128 so as to be routed back toward thedistal tip 174. In the illustrated embodiment, in the pre-deploymentarrangement, the majority of the length of the guidewire 194 ispreferably positioned outside of the deployment catheter 120, havingexited the deployment catheter 120 between the distal end 128 a of thetubular sheath 128 and the distal tip 174.

In the illustrated embodiment, as shown most clearly in FIG. 9,preferably linear grooves or depressions 175 can be formed in the distaltip 174 so that the contralateral guidewire 194 can pass between thedistal tip 174 and the outer sheath 128 without substantially binding orobstructing the free axial movement of the distal tip 174 relative tothe outer sheath 128. In the illustrated embodiment, both ends of thecontralateral guidewire 194 are preferably arranged so as to passbetween the distal tip 174 and the outer sheath 128 and are preferablypositioned within the grooves or depressions 175 preferably formed inthe distal tip 174.

Similarly, with reference to FIG. 12A, the contralateral guidewire 194and the constricted end portion 190 a of the contralateral branch sheath190 are preferably configured so that the contralateral guidewire 194 issubstantially permitted to slide through the opening in the constrictedend portion 190 a of the contralateral branch sheath 190. Accordingly,the tab 200 may be attached to the outside surface of the contralateralguidewire 194 such as by thermal bonding, adhesive bonding, and/or anyof a variety of other securing techniques known in the art. The tab 200is preferably positioned and configured such that, as the guidewire 194slides through the end portion 190 a of the contralateral branch sheath190, the tab 200 is prevented from sliding through the constrictedopening in the end portion 190 a of the contralateral branch sheath 190.In this arrangement, with the contralateral graft tab 200 abuttedagainst the constricted end portion 190 a of the contralateral branchsheath 190, as the contralateral guidewire 194 is further retractedthrough the contralateral iliac artery, the contralateral graft tab 200will cause the contralateral branch sheath 190 to also be retractedthrough the contralateral iliac artery. This will preferably cause thecontralateral branch portion 184 of the graft 178 to be deployed.

Additionally, as is shown most clearly in FIG. 6, the central tube 170,the ipsilateral branch portion 182 of the bifurcated graft 178, and theipsilateral branch sheath 188 are preferably offset within the outersheath 128 from the centerline throughout a portion of the lengthdeployment catheter 120. With reference to FIGS. 3A and 3B, theguidewire lumen 154 through which the central tube 170 preferably passesis also preferably offset within the inner cone 132 to accommodate theoffset of the central tube 170, the ipsilateral branch portion 182, andthe ipsilateral branch sheath 188 from the centerline of that portion ofthe deployment catheter. Offsetting the central tube 170, theipsilateral branch portion 182, and the ipsilateral branch sheath 188provides more space within the outer sheath 128 for the contralateralguidewire 194, contralateral branch portion 184 of the bifurcated graft178, the contralateral branch sheath 190, and the main branch sheath186.

By offsetting the central tube 170, the ipsilateral branch portion 182,and the ipsilateral branch sheath 188 from the centerline of thedeployment catheter, the radial forces exerted on the inside surface ofthe outer sheath 128 from the ipsilateral and contralateral iliacportions of the grafts and sheaths will preferably be reduced. Some ofthe results are, without limitation, that the ipsilateral andcontralateral iliac portions of the grafts and sheaths will preferablybe centered within the outer sheath, and the deployment forces will bereduced. In particular, in some embodiments, with the ipsilateral andcontralateral iliac portions of the grafts and sheaths offset from thecenterline of the deployment catheter 120, extending the inner core 132relative to the outer sheath 128 will require less force than if notoffset, and the compression forces on each of the branches andrespective sheaths in the pre-deployment state will be reduced.

FIGS. 7 and 8 are a side view and top view, respectively, of the mainbranch sheath 186 (also referred to herein as a restraint member) of theembodiment of the deployment catheter 120 shown in FIG. 3, before thedeployment of the main branch portion 180 of the graft 178. FIG. 9 is anenlarged detail view of FIG. 7 taken along the curve 9 in FIG. 7. Withreference to FIGS. 7-9, the distal end 186 b of the main branch sheath186 is preferably tapered or constricted so as to define a smallercross-sectional diameter or size as compared to the main body portion ofthe main branch sheath 186. The smaller diameter of the distal end 186 bpreferably ensures that the main branch sheath 186 will be securedaround the distal anchor member 202 in a manner that will preferablyprevent the main branch sheath 186 from moving or sliding relative tothe distal anchor member 202. As such, the distal anchor member 202preferably defines an annular protruding portion 202 a that preferablysubstantially prevents the main branch sheath 186 from slipping relativeto the distal tip 174. Additionally, in some embodiments, the distalanchor member 202 may comprise a linear groove or depression toaccommodate the passage of the contralateral guidewire 194 (or, asexplained below, one end of the guidewire sheath 216) that can passbetween the distal anchor member 202 and the distal end portion 186 b ofthe main branch sheath 186 in the pre-deployment state.

Any of the main branch sheath 186, the ipsilateral branch sheath 188,and the contralateral branch sheath 190 may be formed from balloon blownpebax, nylon, PET, PTFE, or any other suitable material. In someembodiments, the sheath material is preferably selected so as toincrease the tensile strength of the sheath. Additionally, in someembodiments, the material selected to form any of the sheaths may be atleast partially opaque or colored. This may be beneficial for any of theprocessing that the sheaths may undergo, such as, but not limited to,laser cutting, laser etching, perforating, drilling, threading withsutures, or any of the other processing steps disclosed herein. Forexample, many lasers that are commonly used for etching, cutting,perforating, or other procedures require the sheath material to bepartially opaque for such laser processing.

FIG. 10 is an enlarged section view through the axial centerline of themain branch sheath 186 shown in FIG. 7 taken along the curve 10 in FIG.7. FIG. 11A is a cross-sectional view of the main branch sheath 186shown in FIG. 7 taken along line 11A-11A of FIG. 7, and FIG. 11B is anenlarged detail view of FIG. 11A taken along the curve 11B in FIG. 11A.With reference to FIGS. 7-11B, additional detail regarding the mainbranch sheath 186 and the ipsilateral and contralateral branch portionsheaths 188, 190 will now be described. As previously discussed, in theillustrated embodiment, the main branch sheath 186 preferably partiallyor fully covers the entire length of the bifurcated graft 178, althoughthe main branch sheath 186 may not cover the entire circumference of thegraft 178 along the entire length of the graft 178. The notch 192 ispreferably formed along the portion of the main branch sheath 186 thatis approximately adjacent to the ipsilateral branch sheath 188. Thenotch 192 preferably allows the ipsilateral branch portion 182 of thebifurcated graft 178 to be manipulated away from the contralateralbranch portion 184 of the bifurcated graft 178 before the main branchsheath 186 has been removed.

As discussed above, the portion of the main branch sheath 186 thatpreferably constrains the main branch portion 180 of the draft 178 ispreferably generally tubular shaped, as shown most clearly in FIGS. 7,8, and 11A. Perforations or openings 204 are preferably formed along oneside of the main branch sheath 186. In some embodiments, as in theillustrated embodiment, the openings 204 are preferably linearlyaligned. As will be described in greater detail below, the main branchportion 180 of the bifurcated graft 178 will preferably be deployed fromthe main branch sheath 186 by retracting sheath release wire 166 that ispreferably threaded through each of the openings 204 as illustrated inFIG. 10, propagating a tear along the side of the main branch sheath 186that has been perforated with the openings 204.

In the illustrated embodiment, the openings 204 are preferably spacedapart approximately 0.15 in. In some embodiments, the openings 204 maybe spaced apart less than approximately 0.15 in., or from approximately0.15 in. to approximately 0.2 in., or from approximately 0.2 in. toapproximately 0.25 in. or more. In the illustrated embodiment, each ofthe openings 204 preferably has a circular shape and defines a diameterthat is slightly larger than twice the diameter of the sheath releasewire 166 passing therethrough. Additionally, with reference to FIG. 11C,which is an enlarged view of a portion of FIG. 8, each of the openings204 preferably defines a cut-out or notch 208 formed in a portion of theperiphery of each of the openings 204. In some embodiments, the notches208 are configured to assist the propagation of a tear at each opening204 when the sheath release wire 166 is withdrawn, as will be understoodby one of ordinary skill in the art. In some embodiments, the openings204 may be formed without any notches or cut-outs. In the illustratedembodiment, each of the notches 208 preferably defines a generallytriangular shape. However, the shape of each notch 208 is not solimited, and can define any suitable shape.

However, the shape and the size of each opening 204 is not so limited.Each opening 204 may define any shape that is desired or configured tocause the main branch sheath 186 to tear along the perforated side(i.e., along the openings 204) of the main branch sheath 186. Forexample, without limitation, each opening may have a triangular, square,or diamond shape and may be larger or smaller than the sizes disclosedabove. Additionally, with reference to FIG. 11B, in some embodiments,one or more score lines or depressions 206 may be formed on the insideor the outside surface of the main branch sheath 186 along the tear line(i.e., between each of the openings 204) to help propagate or progress atear along the main branch sheath 186. In the illustrated embodiment,one or more of the openings 204 define a notch 208 formed in a portionof the opening 204, and a depression 206 has preferably been formedbetween one or more of the openings 204.

The sheath release wire 166 can be routed through the openings 204 inany of a number of suitable ways. As shown most clearly in FIG. 10, thesheath release wire 166 is preferably routed through the openings 204 inthe illustrated embodiment of the main branch sheath 186 as describedbelow. As most clearly shown in FIG. 3, the proximal end 166 a of thesheath release wire 166 is preferably routed through the deploymentcatheter 120 so as to be accessible to the medical practitioner. In theillustrated embodiment, with reference to FIG. 3, the proximal end 166 aof the sheath release wire 166 is preferably secured to the tabbedhandle 167 so that the sheath release wire 166 can be manipulated bymanipulating the preferably removable tabbed handle 167. Once thebifurcated graft 178 is in the desired position, as will be described ingreater detail below, the sheath release wire 166 may be pulled orretracted by the medical practitioner to begin propagating tears in themain branch sheath 186, so as to begin deploying the main branch portion180 of the graft 178. Further, portions of the main branch sheath 186may define slits in the segments of the sheath 186 between one or moreof the openings 204, such that the sheath 186 need not be torn at thatportion. FIG. 11D is an enlarged detail view of FIG. 8 taken along thecurve 11D in FIG. 8. With reference to FIG. 11D, in the illustratedembodiment, a slit 210 has preferably been formed near the distal end186 b of the main branch sheath 186, connecting three of the openings204 formed near the distal end 186 b of the sheath 186.

The sheath release wire 166 of the illustrated embodiment of thedeployment catheter 120 can be routed through the openings 204 of themain branch sheath 186 as illustrated in FIGS. 7 and 8 such that thedistal end 166 b of the sheath release wire 166 is secured in a knot 212positioned as shown in the referenced figures. With reference to FIG.10, one suitable routing of the sheath release wire 166 through theopenings 204 is illustrated. In the illustrated embodiment, withreference to FIG. 10, the sheath release wire 166 is preferably loopedaround the each segment of the sheath 186 between each of the holes 204so as to pass through most openings 204 in the sheath 186 at least twotimes. In this configuration, as the sheath release wire 166 is pulledin the directions of the arrows shown in FIG. 10, each of the segmentsof the main branch sheath 186 between each of the openings 204 will besequentially torn by the wire 166 such that the main branch portion 180of the graft 178 adjacent thereto will be deployed. However, many otherroutings or configurations of the sheath release wire 166 and theopenings 204 are anticipated. For example, without limitation, thesheath release wire 166 may also be routed as disclosed in U.S. patentapplication Ser. No. 11/522,292 referenced above, which is fullyincorporated herein by reference.

The main branch sheath 186 can be configured such that the main branchportion 180 of the bifurcated graft 178 can be deployed in a number ofdifferent ways. For example, in some embodiments, the main branch sheath186 can be configured so that the main branch portion 180 can bedeployed first at the distal end of the main branch portion 180 and thensequentially deployed toward the proximal end of the main branch portion180. In some embodiments, the main branch sheath 186 can be configuredso that the main branch portion 180 can be deployed first at theproximal end of the main branch portion 180 and then sequentiallydeployed toward the distal end of the main branch portion 180.Additionally, in some embodiments, the main branch sheath 186 can beconfigured such that the main branch portion 180 of the graft 178 can bedeployed in any combination of deployment directions or sequencesdescribed herein or in any other suitable sequences for the deploymentof the main branch portion 180.

For example, without limitation, the illustrated main branch sheath 186is preferably configured so that, as the sheath release wire 186 isretracted, the deployment of the main branch portion 180 of the graft178 begins at the proximal end of the main branch portion 180 and movestoward the distal end of the main branch portion 180. The tear along theopenings 204 in the main branch sheath 186 will preferably be propagatedby pulling on the sheath release wire 166 until the tear reaches theopening 204 a (illustrated in FIGS. 7 and 8). At opening 204 a, thesheath release wire 166 is preferably routed to the distal end 186 b ofthe sheath 186 so as to bypass the openings 204 between the opening 204a and the distal end 186 b of the sheath 186. At that point, the sheathrelease wire 166 is preferably looped back through the opening 204 b(illustrated in FIGS. 7 and 8) so as to form a loop around the segmentof the sheath 186 between the distal end 186 b of the sheath 186 and theopening 204 b. In this configuration, after the main branch sheath 186has been torn open up to opening 204 a, further retraction of the sheathrelease wire 166 will then preferably begin to propagate a tear from thedistal end 186 b of the sheath 186 toward the proximal end 186 a of thesheath 186. In particular, further retraction of the sheath release wire166 will next preferably propagate a tear along the segment of thesheath 186 between the distal end 186 b of the sheath 186 and theopening 204 b.

As will be described below, in the illustrated embodiment, the mainbranch portion sheath 186 and the sheath release wire 166 havepreferably been configured so that the knot 212 formed at the distal end166 b of the sheath release wire 166 is not positioned adjacent to oraft of the distal end 186 b of the main branch sheath 186. Positioningthe knot 212 fore of the distal end 186 b preferably prevents the knot212 from getting caught or snagged on the distal end of the main branchportion 180 of the graft 178 after the distal end of the main branchportion 180 of the graft 178 has been deployed. In some embodiments,however, the knot 212 can be positioned adjacent to or aft of the aftend 186 b of the main branch sheath 186, or in any other desired orsuitable location. For example, without limitation, knot 212 can bepositioned adjacent to the distal end of the notch 192 formed in themain branch sheath 186, or at any location between the distal end of thenotch 192 and the aft end 186 b of the main branch sheath 186.

Additionally, in some embodiments, the sheath release wire 166 and innercore 132 may be configured and routed as will be understood by one ofordinary skill in the art so that, after the release wire 166 has causedthe sheath 186 to be split and the main branch portion 180 of the graft178 deployed, further retraction of the release wire 166 will withdrawthe main branch sheath 186 partially or fully toward or into theipsilateral iliac artery.

With reference to FIG. 11D, because a slit 210 has preferably beenformed between the openings 204 b and 204 c, after the segment of thesheath 186 between the distal end 186 b of the sheath 186 and theopening 204 b has been torn, the distal end of the main branch portion180 of the graft 178 (i.e., the portion of the main branch portion 180of the graft 178 adjacent to and aft of the opening 204 c) willpreferably be substantially deployed. Further retraction of the sheathrelease wire 166 will preferably propagate a tear in the section of mainbranch sheath 186 between the opening 204 c and the proximal end 186 aof the sheath 186. In the illustrated embodiment, the final segment ofthe sheath 186 that will be torn is preferably the segment of the sheath186 between the openings 204 d and 204 a. Note that, as the segment ofthe sheath 186 between the openings 204 d and 204 a is torn by furtherretraction of the wire 166, the main branch portion 180 of the graft 178will be substantially fully deployed, and the knot 212 formed near thedistal end 166 b of the branch release wire 166 will preferably beretracted by the medical practitioner away from the main branch portion180 of the bifurcated graft 178.

As will be more fully described below, proximal retraction of the outersheath 128 relative to the inner core 132 distal interface of the innercore 132 relative to the outer sheath 188 will preferably release thecompressed iliac branches 182 and 184 of the graft 178 so that they areno longer constrained within the outer sheath 128. The iliac branches182 and 184 will preferably remain compressed and constrained within theipsilateral and contralateral branch portion sheaths 188, 190,respectively, until the sheaths 188, 190 are removed. As mentioned, inthe illustrated embodiment, the ipsilateral branch sheath 188 ispreferably configured to constrain the ipsilateral branch portion 182 ofthe graft 178 in the constrained configuration, for implantation at thetreatment site. The ipsilateral branch sheath 188 is preferablyconnected to the inner core 132 or the interface member 168 and isadapted to be axially proximally withdrawn from the ipsilateral branchportion 182 of the graft 178, thereby permitting the ipsilateral branchportion 182 to expand to its implanted configuration. In one embodiment,without limitation, the ipsilateral branch sheath 188 preferablycomprises a thin walled PTFE extrusion having an outside diameter ofapproximately 0.215 in. and an axial length of approximately 2 toapproximately 3 in. A proximal end of the ipsilateral branch sheath 188can be necked down such as by heat shrinking to secure the ipsilateralbranch sheath 188 to the interface member 168. Similarly, a distalportion of the interface member 168 can flare outwardly to provide abetter securement for the ipsilateral branch sheath 188. In this manner,proximal withdrawal of the inner core 132 (preferably after the mainbranch portion 180 of the bifurcated graft 178 has been deployed) willin turn preferably proximally retract the ipsilateral branch sheath 188away from the main branch portion 180 of the graft 178, therebydeploying the preferably self-expandable ipsilateral branch portion 182of the graft 178. Because the ipsilateral branch sheath 188 ispreferably a tubular sheath with an open end, the ipsilateral branchportion 182 of the graft 178 will preferably be deployed in a top-downdirection (i.e., the portion of the ipsilateral branch portion 182closest to the main branch portion 180 will preferably be the firstportion to deploy).

In the illustrated embodiment, the main branch sheath 186 and thecontralateral branch sheath 190 are preferably connected to thecontralateral guidewire 194, as described above. The contralateralbranch sheath 190 is preferably adapted to restrain the contralateralbranch portion 184 of the graft 178 in the reduced or constrained state.In some embodiments, the contralateral branch sheath 190 preferably hasan outside diameter of approximately 0.215 in. and an axial length ofapproximately 2 to approximately 3 in. In the illustrated embodiment,the contralateral branch sheath 190 can have a smaller cross-sectionthan the ipsilateral branch sheath 188, due to the smaller diameter ofthe contralateral guidewire 194 positioned on the inside of theconstrained contralateral branch portion 184 of the graft 178 ascompared to the diameter of the central tube 170 positioned on theinside of the constrained ipsilateral branch portion 182 of the graft178. Proximal retraction of the contralateral guidewire 194 through thecontralateral iliac artery preferably proximally withdraws thecontralateral branch sheath 190 from the contralateral graft portion184, thereby deploying the contralateral graft portion 184.

FIG. 12A is a schematic representation of the dual concentric guidewireassembly of the embodiment of the deployment catheter 120 shown in FIG.3, showing the position of the main branch sheath 186 and thecontralateral branch sheath 190 before deployment of the main branchportion 180 of the graft 178. FIG. 12B is an enlarged detail view ofFIG. 12A taken along the curve 12B in FIG. 12A. With reference to FIGS.12A and 12B, in some embodiments, the contralateral guidewire 194 may bea dual concentric guidewire assembly 214 comprising a hollow guidewiresheath 216 and an inner core wire 218 that can be axially advancedthrough a lumen 220 in the guidewire sheath 216. The length of thehollow guidewire sheath 216 can be the same as is disclosed for thecontralateral guidewire 194 described above, or any other suitablelength. Any reference herein the guidewire assembly 214 can beinterpreted as a reference to the guidewire 194, since both can be usedinterchangeably.

As previously discussed, in some embodiments, as illustrated in FIGS.12A and 12B, the preferably annular tab 198 may be attached to theoutside surface of the hollow guidewire sheath 216 such that, in use,proximal retraction of the hollow guidewire sheath 216 preferably causesthe tab 198 to engage the main graft sheath 186 so that the main graftsheath 186 can be retracted through the contralateral iliac artery afterdeployment of the main branch portion 180 of the graft 178. As mostclearly shown in FIG. 12B, the main branch sheath 186 may be formedaround an annular ring 222 through which the guidewire sheath 216preferably passes. The ring 222 preferably helps to prevent the tab 198from passing through the proximal end 186 a of the main branch sheath186 so that the main branch sheath 186 can be engaged when the guidewiresheath 216 is retracted.

Additionally, as mentioned above, the preferably annular tab 200 may beattached to the outside surface of the hollow guidewire sheath 216 suchthat, in use, further proximal retraction of the hollow guidewire sheath216 preferably causes the tab 200 to engage the contralateral branchsheath 190 so that the contralateral branch portion 184 of the graft 178can be deployed, and so that the contralateral branch sheath 190 can beretracted through the contralateral iliac artery. In some embodiments,the contralateral branch sheath 190 may be formed around a ring similarto ring 222 described above to preferably further prevent the tab 200from passing through the proximal end 190 a of the contralateral branchsheath 190 so that the contralateral branch sheath 190 can be engagedwhen the guidewire sheath 216 is retracted. Because the contralateralbranch sheath 190 is preferably a tubular sheath with an open end, thecontralateral branch portion 184 of the graft 178 will preferably bedeployed in a top-down direction (i.e., the portion of the contralateralbranch portion 184 closest to the main branch portion 180 willpreferably be the first portion to deploy).

As shown in FIG. 12A, in the pre-deployment arrangement, the main branchsheath 186 is preferably configured so as to at least partially surroundthe contralateral branch sheath 190. The tab 198 is preferablypositioned on the guidewire sheath 216 approximately adjacent to, butbetween the distal end 186 a of the main branch sheath 186 and thedistal end 190 a of the contralateral branch sheath 190. In thisconfiguration, any retraction of the guidewire sheath 216 willpreferably cause retraction of the main branch sheath 186 before thecontralateral branch sheath 190 is retracted.

In the loaded or pre-deployment state, the guidewire sheath 216 ispreferably positioned within the main branch portion 180 of the graft178 such that the distal end 216 a of the guidewire sheath 216 extendsbeyond the distal end of the main branch portion 180 of the graft 178.As is shown most clearly in FIG. 15, in some embodiments, the distal end216 a of the guidewire sheath 216 preferably passes between the distaltip 174 and the outer sheath 128 within a depression 175 preferablyformed in the distal tip 174. In this configuration, as shown in FIG.15, a 0.014 in. guidewire may be advanced through the guidewire sheath216 and into deep thoracic aortic region before (or after) the mainbranch portion 180 of the graft 178 has been deployed.

Additionally, as mentioned above, the contralateral branch tab 200 ispreferably positioned near the distal end 216 a of the guidewire sheath216 at a distance away from the main branch tab 198 that isapproximately greater than the overall length of the main branch sheath186. In this configuration, the main branch sheath 186 will preferablybe substantially completely retracted so that the distal end 186 b ofthe main branch sheath 186 is approximately adjacent to or below (i.e.,closer to the contralateral artery puncture site) relative to theproximal end 190 a of the contralateral branch sheath 190. Thisconfiguration will preferably prevent the main branch sheath 186 frombecoming caught or snagged by the contralateral branch portion 184 ofthe graft 178 when the contralateral branch portion 184 is deployed.This configuration will also preferably reduce the forces that may beinduced on the contralateral iliac artery and other portions of theanatomy during the retraction of the main branch sheath 186 or duringthe deployment of the contralateral branch portion 184.

In some embodiments, the main graft tab 198 is preferably spaced apartfrom the contralateral graft tab 200 by a distance that is approximatelyequal to or greater than the length of the main branch sheath 186. Insome embodiments, the main graft tab 198 is preferably spaced apart fromthe contralateral graft tab 200 by more than approximately 0.5 in. or,alternatively, 0.75 in., less than the approximate length of the mainbranch sheath 186. In the illustrated embodiment, where the main branchrestraint is approximately 7.25 in. in length, the main graft tab 198 ispreferably spaced apart from the contralateral graft tab 200 by at leastapproximately 6.75 in. Further, in the illustrated embodiment, thecontralateral graft tab 200 is preferably spaced apart from the distalend 216 a of the guidewire sheath 216 by approximately 0.75 in. In someembodiments, the main graft tab 198 may be spaced apart from thecontralateral graft tab 200 by approximately 6.75 to approximately 7.5in. or more. Further, in the illustrated embodiment, the contralateralgraft tab 200 may be spaced apart from the distal end 216 a of theguidewire sheath 216 by approximately 1 in. or more.

FIG. 12C is a schematic representation of the dual concentric guidewireassembly 214 of the embodiment of the deployment catheter 120 of FIG. 3,showing the position of the main branch restraint member 186 and thecontralateral branch restraint member 190 after the main branch portion180 of the graft 178 has been deployed. FIG. 12C illustrates a desiredposition of the main graft tab 198 relative to the contralateral grafttab 200 for the illustrated embodiment of the deployment catheter 120.Accordingly, FIG. 12C illustrates a desired position of the main branchsheath 186 relative to the contralateral branch sheath 190 as bothsheaths 186, 190 are being retracted by the guidewire sheath 216 and themain and contralateral graft tabs 198, 200.

As discussed above, the contralateral guidewire assembly 214 can beconfigured to retract or withdraw the main branch sheath 186 after themain branch portion 180 of the graft 178 has been deployed by retractionof the sheath release wire 166. In some embodiments, however, thecontralateral guidewire assembly 214 may be used in place of the sheathrelease wire 166 to deploy the main branch sheath 186. For example,without limitation, in some embodiments, the contralateral guidewireassembly 214 may be configured to exert a sufficient axial force on themain branch sheath 186 to cause the main branch sheath 186 to tear alonga perforated or scored edge of the main branch sheath 186, whether ornot the sheath release wire 166 has been routed through the openings 204in the main branch sheath 186. In these configurations, thecontralateral guidewire assembly 214 may provide a parallel or redundantmeans for tearing the main branch sheath 186 and deploying the mainbranch portion 180 of the graft 178 where the sheath release wire 166has either not been provided or has become damaged or failed.

In some embodiments, the length of the hollow guidewire sheath 216 maybe from approximately 31 in. to approximately 65 in., or alternativelybetween approximately 35 in. to approximately 55 in. In someembodiments, the length of the hollow guidewire sheath 216 may beapproximately 62 in., or alternatively approximately 54 in. In someembodiments, the axial length of the hollow guidewire sheath 216 ispreferably sufficient to extend from a point outside of the body throughan ipsilateral iliac puncture across the bifurcation between thecontralateral and ipsilateral iliacs to a second point outside the bodythrough a contralateral access site. Thus, the length of the hollowguidewire sheath 216 can vary depending upon the intended access sitelocation along the femoral artery and the desired length of theguidewire sheath 216, which is preferably sized and configured to extendoutside of the body, as illustrated most clearly in FIG. 13 discussedbelow.

The hollow guidewire sheath 216 may be formed in any of a variety ofmanners which are well known in the art of catheter body manufacturing,such as by braiding and/or extrusion. In the illustrated embodiment, thehollow guidewire sheath 216 is preferably made of a multi-filar wireNitinol, although any other suitable flexible material may be used andis anticipated herein. Other suitable extrudable materials may includehigh density polyethylene, medium density polyethylene and otherpolyethylene blends, nylon, PEBAX, and others well known in the art.Reinforced tubular bodies may be produced by including a braided layerin or on the wall. The braided wall may comprise any of a variety ofmaterials such as stainless steel, Nitinol, composite fibers and othersknown in the art. Additionally, in some embodiments, the hollowguidewire sheath 216, tabs 198, 200, ring 222, or other components orfeatures on or adjacent to the hollow guidewire sheath 216 or othercomponents of the deployment catheter 120 may further be provided withone or more radiopaque markers 224, such as a gold marker, to facilitatevisualization during placement.

In some embodiments, the hollow guidewire sheath 216 preferablycomprises a PEBAX extrusion, having a braided wire for reinforcing thelumen. The braid filament preferably comprises a round wire having across section of approximately 0.002 in. Alternatively, the hollowguidewire sheath 216 may comprise a stainless steel coil covered by apolyimide tubing that may be covered by PTFE heatshrink. The outerdiameter of the hollow guidewire sheath 216 is preferably betweenapproximately 0.025 in. and approximately 0.045 in., alternativelybetween approximately 0.020 in. and approximately 0.040 in. In someembodiments, the outer diameter of the hollow guidewire sheath 216 ispreferably approximately 0.035 in.

As mentioned, in the illustrated embodiment, the hollow guidewire sheath216 preferably comprises a central lumen 220 extending from the distalend to the proximal end such that the inner core wire 218 may be axiallyadvanced through the central lumen 220. In some embodiments, the centrallumen 220 preferably has an inner diameter of between approximately0.020 in. and approximately 0.016 in., alternatively betweenapproximately 0.019 in. and approximately 0.017 in., in oneimplementation approximately 0.018 in. such that an inner core wire 218preferably having a diameter of no more than approximately 0.016 in. canbe axially advanced therethrough.

The inner core wire 218 may, in the illustrated embodiment 014 in.guidewire. In other embodiments, the inner core wire 218 may be a 0.018in. or a 0.035 in. guidewire, or any other suitable guidewire. In someembodiments, the inner core wire 218 can comprise any of a variety ofstructures, including polymeric monofilament materials, braided or wovenmaterials, metal ribbon or wire, or conventional guidewires as are wellknown in the art. The inner core wire may have a length of betweenapproximately 59 in. (150 cm.) or less to approximately 142 in. (360cm.), alternatively between approximately 71 in. (180 cm.) toapproximately 134 in. (340 cm.), alternatively between approximately 86in. (220 cm.) to approximately 118 in. (300 cm.).

For example, in certain embodiments, the inner core wire 218 may beapproximately 75 in. (190 cm.), approximately 95 in. (242 cm.), orapproximately 118 in. (300 cm.). In general, the length of the innercore wire 218 is preferably between approximately 1.5 to approximately 3times the length of the hollow guidewire sheath such that in use,positive contact may be maintained with the inner wire 218 while thehollow guidewire sheath 216 is being withdrawn from a patient over theinner core wire 218. Positive contact with the inner core wire 218 willprevent friction between the inner core wire 218 and the hollowguidewire sheath 216 from inadvertently withdrawing the inner core wire218 while refracting the as the hollow guidewire. Any of the dimensions,materials, or configurations disclosed herein can be varied widely aswill be appreciated by those of skill in the art in view of the desiredperformance characteristics and manufacturing techniques.

With reference to the embodiments of the deployment catheter 120described above, an exemplary procedure or method of using thedeployment catheter 120 to treat a patient's abdominal aortic aneurysmusing the embodiments of the bifurcated endoluminal graft 178 disclosedabove will now be described. FIG. 13 is a schematic representation of anembodiment of the deployment catheter 120 with the guidewire sheath 216positioned across the bifurcation and within the contralateral iliacartery. The hollow guidewire sheath 216 is preferably introduced intothe ipsilateral iliac artery through an ipsilateral access site in thefemoral artery, advanced superiorly towards the aorta, and usingcross-over techniques known to those skilled in the arts, subsequentlyadvanced inferiorly down the contralateral iliac artery and out acontralateral access site in the contralateral femoral artery. Asdescribed above, the distal end 216 a of the guidewire sheath 216 ispreferably positioned within a groove or depression 175 formed in thedistal tip 174 of the deployment catheter 120. Thus, the distal endportion 216 a of the hollow guidewire sheath 216 is effectively attachedto the deployment catheter 120 while the proximal end 216 b of thehollow guidewire sheath extends from the contralateral access site.

FIG. 14 is a schematic representation, as in FIG. 13, with thedeployment catheter positioned in the aorta. Referring to FIG. 14, afterthe guidewire assembly 214 the has been positioned across thebifurcation in the aorta, the deployment catheter 120 is then preferablyadvanced over a second guidewire 226, such as but not limited to astandard 0.035 in. guidewire, from the ipsilateral access site into theaorta using techniques known to those skilled in the arts. Traction ispreferably applied to the hollow guidewire sheath 216 from thecontralateral access site to take up the slack in the hollow guidewiresheath 216 as the deployment catheter 120 is advanced into the aorta.

At this point, an inner core wire 218 (not shown) may be advancedthrough the hollow guidewire sheath 216, depending on the desires of themedical practitioner. As is illustrated, the hollow guidewire sheath 216has preferably been positioned across the bifurcation and the deploymentcatheter 120 has been advanced into the aorta over a second guidewire226 without the inner core wire being positioned in the hollow guidewiresheath 216. Once the deployment catheter 120 is positioned within thepatient's aorta, an inner core wire 270 can be advanced superiorly fromthe contralateral access site through the central lumen 220 of thehollow guidewire sheath 216. In the illustrated embodiment, the innercore wire 270 can be advanced beyond the distal end 216 a of theguidewire sheath 216 such that the inner core wire 270 can extend beyondthe outer sheath 128 of the deployment catheter 120.

FIG. 15 is a schematic representation, as in FIG. 14, with thecompressed ipsilateral and contralateral branch portions 182, 184 of thebifurcated endoluminal graft 178 positioned partly within theipsilateral and contralateral iliac arteries, respectively. Theipsilateral and contralateral branch portions 182, 184 of the bifurcatedgraft 178 may be exposed as is illustrated in FIG. 15 by proximallyretracting the outer sheath 128 of the deployment catheter 120 whileholding the inner core 132 and, hence, the distal tip 174, in the sameapproximate axial location. As mentioned above, in the illustratedembodiment, in the compressed state, the bifurcated graft 178 ispreferably compressed around the torsion tab 196 that is preferablyrigidly attached to the central tube 170. In this arrangement, after thecontralateral branch portion 184 has been exposed by retracting theouter sheath 128, the bifurcated graft 178 can be rotated so that thecontralateral branch portion 184 is correctly positioned in thepatient's anatomy by rotating the proximal end of the inner core 132 orthe “Y” connector 169 which, in turn, rotates the central tube 170 andtorsion tab 196.

Additionally, because the guidewire sheath 216 preferably forms a halfloop within the outer sheath 128 so as to protrude out of the distal endof the outer sheath 128, as the outer sheath 128 is being proximallyretracted relative to the inner core 132, traction can be applied to theguidewire sheath 216 from the contralateral access site to take up theslack in the guidewire sheath 216 as the outer sheath 128 is beingproximally retracted relative to the inner core 132. Slightly proximallyretracting the deployment catheter 120 and, if desired, the guidewiresheath 216, will preferably position the bifurcated graft 178 asillustrated in FIG. 15. The bifurcated graft 178 is preferablyconfigured so that the contralateral branch portion 184 separates orrotates away from the ipsilateral branch portion 182, as shown in FIG.15, as the outer sheath 128 is proximally retracted.

Alternatively, the ipsilateral and contralateral branch portions 182,184 of the bifurcated graft 178 can be exposed and positioned as isillustrated in FIG. 15 by advancing the deployment catheter 120 (i.e.,advancing the inner core 132 and outer sheath 128 together) up theipsilateral iliac artery toward the aorta. At the point where the distalend of the outer sheath 128 has extended slightly axially beyond thebifurcation of the aorta 228, the medical practitioner can then axiallyadvance the inner core 132 relative to the outer sheath 128 (i.e., byholding the outer sheath 128 stationary) until the ipsilateral andcontralateral branch portions 182, 184 of the bifurcated graft 178 havebeen fully exposed or deployed. Because the distal end of the outersheath 128 has preferably been held in position slightly beyond thebifurcation of the aorta 228, the ipsilateral and contralateral branchportions 182, 184 of the graft 178 will preferably be substantiallycompletely above the bifurcation of the aorta 228. Slightly proximallyretracting the deployment catheter 120 and, if desired, the guidewiresheath 216, will preferably position the bifurcated graft 178 asillustrated in FIG. 15.

FIG. 16 is a schematic representation, as in FIG. 14, with thecompressed ipsilateral and contralateral branch portions 182, 184 of thegraft 178 positioned substantially fully within the respectiveipsilateral and contralateral iliac arteries. As shown in FIG. 16, thebifurcated graft 178 is preferably configured so as to abut against thebifurcation of the aorta 228 or be positioned in the vicinity of thebifurcation of the aorta 228 by retracting the deployment catheter 120and, if desired, the guidewire sheath 216 until the bifurcated graft 178abuts or is in the vicinity of bifurcation of the aorta 228.

FIG. 17 is a schematic representation, as in FIG. 16, with a proximalportion of the main branch portion 180 of the graft 178 or at leastpartially deployed within the aorta. The proximal portion of the mainbranch portion 180 of the graft 178 is preferably partially deployedwithin the aorta as illustrated by proximally retracting the sheathrelease wire 166, as described above, while preferably holding the innercore 132 in a fixed position relative to the aorta so as to preventexerting undue force on the bifurcation of the aorta 228 or otherportions of the anatomy. Deploying the graft 178 in a bottom upsequence, as illustrated herein, may help mitigate the “wind socking”effect that can cause proximal migration of the graft 178. Additionally,deploying the graft 178 and a bottom up sequence may allow for eitheraxially or rotationally repositioning of a partially deployed graft 178without causing significant or any damage to the arterial wall. In someembodiments, this may partly be due to the fact that the deployed middleportion of the graft 178 may move against the arterial wall more easilythan a deployed end portion of the graft 178.

FIG. 18 is a schematic representation, as in FIG. 17, with a proximalportion and a distal portion of the main branch portion 180 of the graft178 partially deployed within the aorta. The distal portion of the mainbranch portion 180 of the graft 178 is preferably partially deployedwithin the aorta as illustrated by further proximally retracting thesheath release wire 166, as described above, while still preferablyholding the inner core 132 in a fixed position relative to the aorta soas to prevent exerting undue force on the bifurcation of the aorta 228or other portions of the anatomy.

FIG. 19 is a schematic representation, as in FIG. 18, followingdeployment of substantially the entire length of the main branch portion180 of the graft 178 within the aorta. The remaining constrained portionof the main branch portion 180 of the graft 178 is preferably deployedwithin the aorta as illustrated by further proximally retracting thesheath release wire 166, as described above, while still preferablyholding the inner core 132 in a fixed position relative to the aorta soas to prevent exerting undue force on the bifurcation of the aorta 228or other portions of the anatomy.

Because the distal end the hollow guidewire sheath 216 extends beyondthe distal end of the main branch portion 180, an inner core wire 218can now be advanced through the guidewire sheath 216 so that the tip ofthe inner core wire 218 will not catch on the endoskeleton or wireframeof the expanded main branch portion 180 as the inner core wire 218 as itis advanced distally through the lumen of the main branch portion 180.The inner core wire 218 may be advanced through the distal end of thehollow guidewire sheath 216 such that, when the hollow guidewire sheath216 is withdrawn, the inner core wire 218 will preferably remainpositioned through the central lumen of the expanded main branch portion180 of the bifurcated graft 178 to provide subsequent access to the maingraft 178 as well as superiorly within the patient's aorta. In someembodiments, the inner core wire 218 preferably has a length at leasttwice as long as that of the guidewire sheath 216, such that physicalcontact can be maintained with the inner core wire 218 while the hollowguidewire sheath 216 is being withdrawn over the inner core wire 218. Inthis configuration, potential friction between the inner core wire 218and the hollow guidewire sheath 216 is preferably prevented frominadvertently withdrawing the inner core wire 218 as the guidewiresheath 216 is withdrawn. Note that the inner core wire 218 could alsohave been advanced distally through the lumen of the guidewire sheath216 during any of the previous steps described above.

As such, FIGS. 17-19 illustrate an embodiment of the main branch sheath186 in which the main branch portion 180 of the graft 178 is initiallydeployed in a bottom-up sequence and then in a top-down sequence.However, the embodiments of the main branch sheath 186 and thedeployment catheter 120 are not so limited. The main branch sheath 186and the deployment catheter 120 can be configured to deploy the mainbranch portion 180 of the bifurcated graft 178 in any desired orsuitable sequence to address different clinical situations or needs,such as, but not limited to, a top down sequence. For example, for athoracic aneurysm, it may be beneficial to configure the main branchsheath 186 so that the main branch portion 180 deploys in a bottom-upsequence. Additionally, as mentioned above, for some clinicalsituations, deploying the main branch portion 180 of the graft 178 asdescribed above may be beneficial because it may mitigate a “windsocking” or “sailing” effect and also preferably prevent the knot 212from becoming caught on the distal edge or distal portion of the mainbranch portion 180 of the bifurcated graft 178 or between the distalportion of the main branch portion 180 and the wall of the aorta afterthe main branch portion 180 of the bifurcated graft 178 has beendeployed.

FIG. 20 is a schematic representation, as in FIG. 19, following thepartial retraction of the guidewire sheath 216 and the main graft sheath186 through the contralateral iliac artery. Note that, as illustrated inFIG. 20, the main graft sheath 186 has preferably been split apart asdescribed above so that a tear has been propataged along substantiallythe entire length of one side the main graft sheath 186. As theguidewire sheath 216 is preferably proximally retracted through thecontralateral artery, once the main branch tab 198 abuts the proximalend 186 a of the main branch sheath 186, further proximal retraction ofthe guidewire sheath 216 will preferably also retract the main graftsheath 186. Withdrawing the main graft sheath 186 through thecontralateral iliac artery, when the deployment catheter 120 has beenrouted through the ipsilateral iliac artery as shown prevents anyinterference between the main graft sheath 186 and the outer sheath 128or other components of the deployment catheter 120 as the main graftsheath 186 is being withdrawn.

In the illustrated embodiment, the main graft tab 198 is preferablypositioned on the guidewire sheath at a sufficient axial distance awayfrom the contralateral branch tab 200 such that the main branch sheath186 will preferably be substantially retracted past the contralateralbranch sheath 190 before the contralateral branch portion 184 isdeployed. As illustrated in FIG. 20, the guidewire sheath 216 haspreferably been proximally retracted to the point where thecontralateral branch tab 200 has first abutted the proximal end 190 a ofthe contralateral branch sheath 190.

FIG. 21 is a schematic representation, as in FIG. 20, following thefurther proximal retraction of the guidewire sheath 216 and,consequently, the contralateral branch sheath 190, through thecontralateral iliac artery. As illustrated therein, the contralateralbranch sheath 190 has been retracted so as to completely deploy thecontralateral branch portion 184 of the bifurcated graft 178. Ifdesired, the inner core wire 218 can be manipulated as described aboveso as to remain in the position illustrated in FIG. 21. The main branchsheath 186 and the contralateral branch sheath 190 can be then withdrawnfrom the patient through the contralateral access site. Accordingly, inthe illustrated embodiment the main branch sheath 186 and thecontralateral branch sheath 190 are introduced into the patient throughthe ipsilateral access site and then removed from the patient throughthe contralateral access site. In modified embodiments configured forother portions of the patient's anatomy, the main branch sheath 186 andthe contralateral branch sheath 190 are introduced through a firstvessel and then removed from the patient though a second vessel.

FIG. 22 is a schematic representation, as in FIG. 21, following theproximal retraction of the ipsilateral branch sheath 188 and deploymentof the ipsilateral branch portion 182 of the graft 178. The ipsilateralbranch portion 182 of the graft 178 may be deployed by proximallyretracting the inner core 132 which, as described above, is preferablydirectly or indirectly rigidly attached to the ipsilateral branch sheath188. Because the ipsilateral branch sheath 28 is preferably anopen-ended tubular sheath, the ipsilateral branch portion 182 of thegraft 178 is preferably deployed in a top down sequence.

However, the ipsilateral branch sheath 188 (and the contralateral branchsheath 190) can be configured to accommodate any other desired orsuitable sequence. For example, in some embodiments, the ipsilateralbranch sheath 188 (and the contralateral branch sheath 190) can beconfigured to be a perforated sheath similar to the main branch sheath186 described above, wherein a sheath release wire could be routedthrough the perforations to deploy each of the branch sheaths 188, 190in either a top-down, a bottom-up, or in any other desired direction orcombination thereof. Also, note that the guidewire 226 can be retractedsimultaneously with the deployment catheter 120, or can be retracted atany time preferably after the deployment catheter 120 has beenpositioned in the desired location within the aorta.

FIG. 23 is a schematic representation, as in FIG. 22, of the deployedbifurcated graft 178 with the inner core wire 218 positioned within themain branch portion of the deployed graft. As shown in FIG. 23, theinner core wire 218 can remain positioned in the patient's aorta,providing continued access to the graft and the aorta through thecontralateral iliac artery. Thus, any variety of diagnostic and/ortherapeutic procedures may be accomplished following the implantation ofthe bifurcated graft and that require guidance can use the inner corewire 218. For example, the inner core wire 218 may be used to guide aballoon dilation catheter to the graft site to dilate a stenosis,re-expand a portion of the graft or perform other touch up procedures.Alternatively, the inner core wire may be used to guide a subsequentcatheter to the graft location for deploying a cuff either in the aorta,for example at the distal end of the main graft segment, oralternatively in the iliac artery at the proximal end of one of thebranch graft portions. In addition or in the alternative, those of skillin the art will recognize that a variety of other therapeutic and/ordiagnostic catheters or instruments that require guidance can alsoutilize the inner core wire 218.

For certain post-implantation procedures, the catheters, such as thedilation catheter or cuff deployment catheter described above, may beconfigured to be advanced over a smaller diameter, more flexible wiresuch as the inner core wire 218. However, for certain devices, thesmaller diameter of the inner core wire may not provide enough strengthor stability to guide the catheter to the treatment site. For example,many catheters are currently designed to be delivered over a 0.035 in.guidewire, and thus an inner core wire which has a diameter ofapproximately 0.014 in. may not provide enough stability over which toguide the catheter.

In such cases, an exchange catheter having an inner diameter greaterthan the diameter of the desired guidewire may be advanced through thecontralateral access site over the inner core wire 218. Once theexchange catheter has been advanced to the distal end of the inner corewire 218, the inner core wire 218 may be proximally retracted throughthe contralateral access site. A larger guidewire, such as a 0.035 in.guidewire may then be advanced through the exchange catheter to the mainbranch portion. Once the larger guidewire has been advanced through theexchange catheter, the exchange catheter may be proximally withdrawnfrom the contralateral access site, leaving the larger diameterguidewire in position in the patient's contralateral iliac and extendingthrough the main branch portion. Thus, the smaller diameter inner corewire may be exchanged for a larger diameter guidewire more suitable foruse with larger instrument catheters without encountering any of thecomplications associated with trying to advance a guidewire having acurved distal tip through a deployed graft portion.

The exchange catheter may comprise an elongate flexible tubular bodyhaving a single lumen with an inside diameter of at least approximately0.003 in. greater than the outer diameter of the desired procedureguidewire. The body may include a helical coil, braid, or weave withinthe tubular wall, to resist kinking, as is understood in the art. Aproximal hub may be provided on the tubular body, to facilitate graspingand removal of the exchange catheter following placement of the desiredprocedure guidewire.

While the above description has shown, described, and pointed out novelfeatures as applied to various embodiments, it will be understood thatvarious omissions, substitutions, and changes in the form and details ofthe device or process illustrated may be made without departing from thespirit of the disclosure. Additionally, the various features andprocesses described above may be used independently of one another, ormay be combined in various ways. All possible combinations andsubcombinations are intended to fall within the scope of thisdisclosure.

As will be recognized, certain embodiments described herein may beembodied within a form that does not provide all of the features andbenefits set forth herein, as some features may be used or practicedseparately from others. The scope of the inventions is indicated by theappended claims rather than by the foregoing description. All changeswhich come within the meaning and range of equivalency of the claims areto be embraced within their scope.

For example, while the delivery system is described with respect todeploying a bifurcated stent in the abdominal aortic and leaving aguidewire positioned through the expanded stent, it is furtherenvisioned that the delivery system could be used to deliver aprosthesis having a main portion and at least one branch portion, oralternatively a prosthesis having only a straight, main branch portion,to other branched intravascular vessels (e.g., the thoracic aorta and acardiac artery) and leave a guidewire positioned through the expandedprosthesis.

1. An endoluminal vascular prosthesis deployment system for deploying anendoluminal vascular prosthesis having at least a main branch and afirst branch, comprising: a flexible catheter body that comprises anouter sheath with a proximal and distal end, an inner core that extendsthrough the outer sheath and is axially moveable with respect to theouter sheath, and a distal tip that is positioned adjacent the distalend of the outer sheath and is coupled to the inner core; a main branchrestraint that comprises a tubular member that surrounds and constrainsat least the main branch portion, the tubular member having a firstportion adjacent a first end of the tubular member, a second portionadjacent a second end of the tubular member, and an intermediate portionpositioned between the first and second portions; the tubular membercomprising a plurality of perforations, a release wire extending throughthe plurality of perforations and configured to tear portions of thetubular member of the main branch restraint between the perforations todeploy the main branch portion when the release wire is proximallyretracted by releasing at least one of the proximal portion orintermediate portion before the distal portion; a first branch restraintthat comprises a tubular member configured to releasably constrain thefirst branch portion, the first branch restraint coupled to a firstbranch release mechanism.
 2. The deployment system of claim 1, whereinthe release wire is configured to release the proximal portion beforethe distal portion.
 3. The deployment system of claim 2, wherein therelease wire is configured to release the distal portion before theintermediate portion.
 4. The deployment system of claim 1, wherein therelease wire is configured to release the intermediate portion beforethe distal portion
 5. The deployment system of claim 1, furthercomprising a guidewire lumen extending through the inner core.
 6. Thedeployment system of claim 1, wherein the main branch restraint definesa first end portion and a second end portion, and the release wire isrouted through the perforations such that an end of release wire ispositioned between the first end portion and the second end portion ofthe main branch restraint.
 7. The deployment system of claim 1, whereinthe main branch restraint comprises a score line between at least someof the perforations.
 8. The deployment system of claim 1, wherein themain branch restraint comprises a slit between at least some of theperforations.
 9. The deployment system of claim 1, wherein thedeployment system further comprises a hollow guidewire slidablypositioned within the deployment catheter.
 10. The deployment system ofclaim 9, wherein the deployment system further comprises an inner corewire slidably positionable within the hollow guidewire.